Electromagnetic sound-reproducing system



C. R. ROWE ELECTROMAGNETIC SOUND REPRODUCING SYSTEM June 5, 1.928.

Filed Jan. 28, 192s 2 Sheets-Sheet l A TTONEY June 5, 1928. 1,672,173

c.A R. RowE ELECTROMAGNETIC SOUND REPRODUGING SYSTEM Filed Jan. 28, 1926 2 sheets-sheet 2 *TEE d 5 tid/ff 6 @Q9 ji: vezz for Q j ATTORNEY Patented June 53.1928.

UNITED STATES 1,612,113` PATENT ivoFFlcE.

' oHARL'Es R. RowE, or EAST ORANGE, NEW JERSEY, AssreNoR rro EEANDESLAEORA- ToRIEs, JN0., or NEWARK, NEW JERSEY, A CORPORATION or NEW JERSEY.

ELECTBOMAGNETIC SOND-IREPRODUCINGl SYSTEM.

Application; meu January ,My invention relates broadly to'l electromagnetic sound reproducers and more particularly to a `circuit arrangementfor sound reproducers b which high efficiency and v goodtone vqua ity may be obtained 1n sound lreproduction over the entire scale of musical notes. I

`One of the objects of my invention is to rovide an electromagnetic sound reproduc# l0 lng system in which a plurality 'of electron tube circuits are arranged to integrate the effect of signaling energy upon an electromagnetic system for reproducing sound at relatively large volumes Another object of my invention is to prov vide an electromagnetic sound reproducing system in which a plurality of electron tube circuits are, associated with a like number of electromagnetic driving devices arranged to operatev upon acoinmon vibratory mem-V ber .integrating the effect of signaling energy existing in each of the electron tube circuits for actuation of the sound reproducsystem. l

in v Itill another object vof my invention is torovide an electromagnetic sound Areproduclng system in which independent electron tube circuits' are arranged Ito control Aindes pendent electromagnetic driving units which 30 actuate a common. vibratory member, one

lofthe driving units being designed for eicient operationover frequencies within a portion of the musical scale 'and the. other of said driving units being designed for cicient reproduction at frequencies over the other portion of the musical scale, whereby the entire range of musical notes may be efficiently.. reproduced.

A further object of my invention` is to provide an electron tube amplification system forv operation .of an' electromagnetic sound'reproducing apparatus which .will efficiently respond overfvthe ent-ire range of musical notes for the ecient reproduction of sound at large volume and good tone quality.

Other and .furtherJ` objects of my 'invention' -will be understood from the specification hereinafter following, by reference the,

accompanying" drawings, in which: v

Figure illustratesldiagrammatically the circuits o a sound reproducing/system in association with a radio receiving apparatus -for the. genergy;

rproduction of4 broadcast signaling- 1g. 2 is"v an; enlarged theoretical 2s, 192s. serial m. 84,497.

quality of the reproduced sound; Fig.`4 il lustrates diagrammatically an arrangement l(of windings in a common electromagnetic system with the windings disposed in separate electron tube circuits and each designed to, respond efficiently to frequencies overa portion ofthe musical-scale; Fig. 5 illustrates anotherl circuit arrangement for the electromagnetic devices in the output circuits of independent tube systems; and Fig.

6`shows a circuit arrangement of a plurality of electron tubes and independent electromagnetic driving devices each eiiciently rel sponsive to a parti-cular, range of notes for the reproduction of all of the received tones at pleasing quality.

Heretofore in the art it has been diiiicult to reproduce sound etliciently over the entire musical'scale. Loud Speakers have been constructed to reproduce a .portion of the musical scale with pleasing tone quality, but in doing so the tone quality of another portion ofthe'musical scale has been s'acriiced. In the middle register, that is, the range of 'frequencies vwhich"the speaking voice normally' occupies, electromagnetic sound reproducers in general will be altogether vsatlsfactory; however, injfthe reproduction of a violin solo where a varied range of high and low notes must be reproduced with a piano accompaniment such loud speakers normally lose" the natural reproduction of the tones.

`My electromagnetic sound reproducing system has been developed with a view of securing ellicient -reproduction of all of the'notes in the musicalscale. The operation of the circuits results in bringing out a wealth of perfectly natural tones. A mellow, full, complete harmony without a trace of nasall tone may be reproduced; The fuller harmonic's,` wider range, and clarity os'sible in the electromagnetic sound re rodrilcer of my invention has a definite an satisfying reality. f

' I provide independent electron tube amplification' systems where the incoming signaling energy is delivered to a. common input circuit but controls independent output.

vui

v 12A and-12Il wound upon electromagnetic sysdevice is exerting repulsive forces upon the 'vibratory member. I may also arrange the electromagnetic driving systems in circuit arrangements where one system is eiiciently responsive to frequencies over a portion of the musical scale, while the other .driving system is efficiently responsive over another -portion'of the musical scale, thereby securing a blending of the reproduced notes for eiicient reproduction of sound overl the en-.

tire musical scale.

' Referring to the drawings, my invention is illustrated in Fig. 1 as applied to a. broadcast" receiving system having an antennaground. radio frequency pick up circuit 1-2 with'a radio frequency amplifier comprising electron tubes 3 4 connected therewith, Va detector tube 5 connected to the output of the radio frequency ampliiier, and an impedance coupled audio frequency 'amplifier system'consisting of tubes 6-7 andthe separate Velectron tube circuits which connect with electron tubes 8 and 9 connected withv the output-thereof. Electron tube 8 contains cathode' 8, grid 8"' and plate 8", and correspondingly, electron tube 9 contains cathode 9.", grid electrodel 9", and plate electrodes 9. The input circuits of each of the tubes be'- tween grid electrode 8b and cathode 8, and grid electrode 9b and cathode 9, are connected through an impedance coupled audio frequncy amplifier constitutedV by tubes 6 In theutput circuit offelectron tube 8 I provide windings 11 and 11a connected in series and wound upon the electromagnetic system 17 having. a magnetic reluctance gap 26 therein. In the output circuit of electron tube 9 I provide a pair of windings tem 18 having magnetic reluctancegap 27.

-The electromagnetic systems are both arranged to actuate arcommon vibratory member 14 which may be connected thr'ough a rod 15 with a sound reproducing diaphragm 16. Sources of potential are provided for energizing the cathode circuit for each ofA the tubes astre-.presented at 21. The plate supply for detector tube 5 is connected across terminals '20. while the plate supply for the" amplifying tubes 3, 4, 6, 7 and the divided tube circuit 8 9 is supplied throughter- -mnals 19-29. A f

In Fig. 3 I have illustrated Vthe electro; magnetic driving i connected therewith.

systems disposed' in .the .output circuits of Veach' of the tubes 89 .where the windings 11-11a and 12'12a` are removed from direct connection in the plate clrcults and connectedA 1n such manner that "windings 11 and 11a are related toan audio frequency choke-coil 22 and condenser 23, While windings 12*l2al are related to an audio frequency chokev coil 25 and a condenser 24.' A midtap connection 28 between the separate sets of windings is taken to the source of filament lighting potential 21.

In Fig. 4 I have illustrated the windings 11-111L and 1.2-12a disposed on the same set of pole pieces 17 where one set of Windings 11-11 is designed for eticient repro- 'duction at high frequencies, that is 'to say the windings have a relatively low impedn ance, and windings12i12a-lon the other hand are designed for efficient' reproduction of the lower frequencies and have a relatively high impedance. Theconjoint effect of these windings on the vibratory memberA 14 is to secure etcient reproduction overthe lentire range of musical notes.

In Fig. 5 I have shown the separate electromagnetic driving devices connected through transformer systems 30 and 31 with the output circuits of tubes'S and 9.

, In Fig. 6 I have illustrated an electromagnetic sound reproducing system-wherein tubes 8, 9 and 32, each excite the windings 11"*11, 12-12, and 33-33a, operatlng upon electromagnetic systems and armatures each Aarmatures 14, 34 and 35, respectively, the.

being eiciently responsive, so that in aggre-` Y gate the resulting effect. -is a substantially perfect blending of all frequencies over a particular range of notes. The several armatures may be connected to different sound reproducing diaphragms of diifering natural periods; A

The operation of the electromagnetic sound reproducing system isV such that with the two plate circuits of tubes 8 andv 9 operating in phase, the electromagnetic windings 11- 11a will develop repulsive forces with re' spect to vibratory 'member 14, while windings 12 and -121 ydevelop attractive Vforces upon vibratory member 14 for imparting vibrations to the member 14 which are repro rluced by a sound reproducing diaphragm In .the circuit arrangements illustrated in Figs. 3', 4 and 5 the i VIt will be observed that the. electromag- V-netic driving units are arranged in sets on diametrically opposite sides pf the common ing 12 is located are normally south, while the pole pieces on which lwinding 412a is located are normally north. The impressionof incomingr signaling energy on the input circuit results in the operation of the plate circuits in phase and when winding 11 tends to reduce the strength of the normally -north pole,'winding 11a tends to similarly reduce the strength of the normally south pole. Electron tube 9 operates simultaneously so that winding 12a tends to strengthen the normallyl north pole; resulting in attraction of the vibratory member 14 in the direction of windings 12 and 12a and vwith the releasing of magnetic force by windings 11 and 11a. The next succeeding'cycle will reverse the order of operation and in this manner reproduction at relatively large volume may be obtained.

While I have described my invention' in l certain preferred embodiments, I desire that it be understood that modifications may be made and that no limitations upon the invention are intended other .than those im- 'posed by the scope of the appendedclaims.

Having thus described my invention, what I claim and desire to secure by Letters Patent of the UnitedStates is as follows:

1. In an electromagnetic sound reproducing system, an electron tube amplitication circuit. a pair of electron tubes having a common input circuit connected with ysaid amplification circuit. an independent output -circuit connected with each of said pair of ing the amplitude of incoming signaling energy, a pair of electron tubes having a 'common `input circuit connected with said amplification circuit independent output circuits for eaclioof said ,electron tubes, an

^ electromagnetic winding in each of saidoutput circuits, ''a^c'ommon ,vibrator'y member actuated by said electromagnetic windings,

ythe effects of' said signaling said pair lof electron tubes being operated in phase whereby one of said electromagnetic windings exerts attractive forces on said vibratory member, while the other of said electromagnetic windings exerts repulsive forces thereon. f

'3; An electromagnetic sound reproducing system comprisingr in combination an elec'- tron tube amplification circuita pair of electron .tubes havingva common' input circuit connected with said amplification circuit, 'independent output circuits for said electron tubes, a pair of vdiametr'ically opppsed electromagnetic windings, connections tween one of said windings and one of said.

output circuits and connections between the other of said windings and the other of said output circuits, and a common vibratory member positioned between said electromagnetic windings. and actuated by signaling energy impressed upon said common input circuit. v

4. An electromagnetic sound reproducing system comprising in combination an elec'- tron tube amplification circuit, a pair of electron tubes having a common input circuit connected with said amplilication circuit, independent output` circuits for said electron tubes, sets of -oppositely wound electromagnetic windings connected in yeach of said output circuits for producing poles of opposite polarity, said sets of electromagnetic windings being arranged diametrically opposite each other with poles of opposite polarity adjacent each ot-her, and .a ,common vibratory -member situated lbetween said sets of electromagnetic windin the conjoint etl'ect' thereo upon the impression of signaling energy upon said common input circuit.

5. An electromagnetic sound reproducing .l

system. comprising in combination a'pair of space discharge devices each including grid, filament and plateC electrodes, anv input circuit common to each of said grid and fila- Aoutput circuits, a common -vibratory meinber` arranged to be actuated by said electromag' netic windings, and circuits for passing cur-'Q rents in phase 'through each o f said independent electromagneti@ windings and and actuated by ment electrodes, means for impressing sig-,-

naling energy upon said input circuit, indev through the space vpath` betweensaid plate and filament electrodes in phase, integrating I energy upon said common -vibratory member.

6. "In an electromagnetic sound reproduc- .ingsystem an electron tube amplification circuit, a plurality offelectron tubes, a common` input circuit for said tubes connected with .said amplification circuit', independent output circuits forl each of said electron tubes,

f4 y 1,672,17a

an electromagneticwinding disposed in each of said output circuits, said electromagnetic windings each being responsive to a diierent range of audio frequency notes and a single armature member upon which said electromagneticwindings are each effective. 7. In an electromagnetic sound reproduc- `ing system an' electron tube .amplification circuit, a iluralityof electron tubes each having gri filament and plate electrodes, a.

` single circuit including allof said `grid electrodes, separate circuits, each including onel of said plate electrodes,. an electromagnetic Winding included in series connection with each of said plate electrodes, each of said electromagnetic windings being efficiently re-A testimony whereof I ailix my signature. 20

' cHABfnEs R. RoWE. 

